A machine is typically powered by an electrical power source and typically has an on/off switch for use during normal operating conditions. For safety reasons, a machine will usually also include an emergency stop device for terminating electrical power to the machine in an emergency situation. While the design of an emergency stop device may vary greatly, the device will generally include a switch which converts from a normal state to an emergency state when an emergency stop is necessary and a controller which controls the power source for the motor or machine. The switch and controller typically are enclosed in a housing or casing to protect them against weather, dust, explosive situations, or other hazards presented by the environment of the particular machine.
In a more sophisticated emergency stop device, the switch will include a circuit board including, among other things, a series of contacts that are either normally closed or normally open contacts. The controller in a sophisticated emergency stop device will usually include a microprocessor for appropriating controlling the machine's power source in an emergency situation. The switch, and specifically its contacts, are usually considered component most vulnerable to damage and deterioration. However, in view of the criticality of the switch in the operation of the emergency stop device, a faulty contact must be replaced or else the machine will not run until the relays are replaced. For this same reason, the ability to periodically inspect and/or test switch components could be a very important part of a preventive maintenance plan but such inspection/testing is not always possible or at least not practical.
Accordingly, the inventor appreciated that a need remains for an emergency stop device which allows efficient and convenient replacement, inspection and/or testing of the switch components.